[TowerTalk] Non-Guyed Support for 80m Horizontal Loop at 35 feet

[Al Kozakiewicz]

I'm no structural engineer, so perhaps someone else can bluntly point out what a stupid idea this is.

What about filling the pipe with foam, the kind used in boat building?  It's light and pretty strong when encased. If I calculated correctly, a 40' length of 4" pipe is only about 4 cubic feet, which is a modest amount of foam and should not be hideously expensive.  The only real load on the structure is wind.

Telephone poles are a really good idea if you can find them.

Al
AB2ZY

 

-----Original Message-----
From: towertalk-bounces at contesting.com [mailto:towertalk-bounces at contesting.com] On Behalf Of Rick Karlquist
Sent: Saturday, February 05, 2011 8:31 PM
To: jdolson at laconic-designs.com
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Non-Guyed Support for 80m Horizontal Loop at 35 feet

J. Dolson wrote:

> 3. The soil is heavy clay.

> 1. I have several 40 foot lengths of 4" diameter aluminum irrigation pipe.
> If they were to be filled with cement and dropped five feet into the 
> ground would it be stiff enough to stay vertical?
>
> 2. If that is not feasible, then could I fill say a 15 foot length of 
> pipe with cement, drop it 5 feet into the ground, and attach a guy 
> wire to the

Regarding heavy clay soil.  We have that here.  When it gets wet, it has a consistency like peanut butter.  Self supporting poles dropped 5 feet in the ground...aren't.  12 inch post holes filled with concrete don't work either (and this is just for holding up a 40 meter vertical.  You have to have a real tower base, like 3X3X6 feet in wet clay soil.

Regarding irrigation pipe.  It is wonderful when guyed, but cannot even support itself in the wind.  Filling it with unreinforced concrete is crazy.

The solution to the horse problem is as follows:

Connect 4 horizontal legs at the bottom of the mast at right angles to the mast and to each other.
These legs are buried just beneath the ground (so horses don't trip over them).  The ends of the legs are secured to the ground with screw in guy anchors, screwed all the way into the ground so they are flush.  The legs should be 5 to 10 feet long; you'll have to do the engineering.  You'll need gussets where the legs connect to the mast.  This avoids digging holes and filling them with concrete like a real tower.

Rick N6RK

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